Home

Detailed specifications

Effectively communicating design solutions to the internal stakeholders

detailed specifications

The detailed user interface specification -- 'detailed specification' in short -- defines the user interface in every detail, in all its aspects. It defines the problem the user interface is intended to solve and outlines the approach used to reach the solution. It resembles the blueprints an architect produces for a building.

Besides being a blueprint, the document also is a means of communication design decisions and their rationale. It communicates interaction flow from a high level perspective (interaction framework) to the nitty-gritty detail. It provides a common terminology to guide discussions concerning the user interface and it documents the issues, concerns and decisions that were made during the design process.

When designing a user interface, the interaction designer has gone through the effort and trouble of creating mock-ups, illustrating work flows and tasks to be performed. These more-or-less realistic representations of the user interface may be handed over to the developer team for implementation, but this does not guarantee a consistent and uniform implementation of the design. So, when going through the effort of creating a usable interaction design, tailored to the user’s needs, you also want to make sure your design is implemented consistently. The user interface specification helps to assure that the software is built in line with your design intentions.

A design specificaiton can serve these goals:

  • Elicit feedback from an early stage in the project.
  • Guarantee consistency in the design of the final product
  • Perform change management
  • Educate the team
  • Make the project more cost efficient
  • Evaluate coverage of requirements
  • Reduce the risk of losing requirements through the process

A detailed specifications can take all forms and shapes. Depending on the objectives the specification needs to meet, it can be an annotated design (e.g. drawings with call-outs), an illustrated specification (e.g. text with mock-up illustrations), a formal specification (e.g. text with behavioural models in UML), a design rationale (describing design options and arguments for decisions), a decision model (with a decision tree to guide the designer) or a style guide (with reusable design patterns).

Effort: 

The effort for writing detailed specifications is very scalable. With little effort annotated designs can be made which can be sufficient for smaller applications or agile development processes. When compliance, security or safety are at stake, detailed specifications may need to be extremely detailed, requiring the same amount of effort as the design itself.

However, much more important in terms of effort and quality than the initial writing of the detailed specification, are

  • the maintenance of the specification during and after developement
  • the testing of the compliance of the development to the specification

Related